Update, official 4.4+MF2.3.10, beta 4
1. ART is available. but your application storage must be over 2G.
Reboot time with no user apps is about 3 mins. more apps, and more time it need.
2. Optimized power consumption , especially when the music player is on.
3. Solved: When using Bluetooth connection, alarm clock, speaker and headphone are silent.
4. Solved: power-saving mode doesn't work after reboot
other changes are related to We Chat, an app.
You need to unpack that file first , then install the resulting file.
hasz's MIUI, 4.8.29 full package: http://pan.baidu.com/s/1sjx2gTR
4.8.22 to 4.8.29 OTA package: http://pan.baidu.com/s/1B3TzK
WARNING: MIUI do NOT support ART, so please do not force to open it
ZTE GRAND SII LTE (S291)